Marine foundation and method of construction



H. E. GROSS April 1, 1941.

CONSTRUCTION Original Filed Dec. 31, 1937 6 Sheets-Sheet 1 Hal 0m: @055N NT Ii \L.

I VE OR IATTQRNEY I April 1941- H. E. GROSS 2.236.682

IARII lE FOUNDATION AND METHOD OF CONSTRUCTION Original Filbd Deq.- 31,1937 6 She sts-Sheet 2 f/E/VQVZ 6 9055 INVENTOR ATTORN EY April 1, 1941.H. E. GROSS MARINE FOUNDATION AND METHOD OF CONSTRUCTION 31, 1937 6Sheets-Sheet 3 Original Filed Dec.

flf/MQVE 6905.5 INVENTOR ATTORN EY \w an Ap 1941- H. E. GROSS 36,682

amiss rouummou m urn-non or consnwcnou Original Filed Dec. 31, 1937 6Sheets-Sheet 4 HE/VQVE 6m;

INVENTOR A'I I'ORNEY April 1, 1941. GROSS 2,236,682

MARINE FOUNDATION AND METHOD OF CONSTRUCTION Original Filed Dec. 31,1937 6 Sheets-Sheet 5 INVENTOR ATTORN EY April 1, 1941. H. E GROSSIARINE FOUNDATI ON AND IETHOD 01'' CONSTRUCTION Original Filed Dec. 31,1937 6 Sheets-Sheet 5 flf/VQV Z: 6;?055

INVENT My 7 ATTOR Patented Apr. 1, 1941 UNITED. STATES PATENT A OFFICE Iazsacsz I mama rooms-non AND mz'rnon or consrauc'non Henry Emmett Gross,College Station, Tex ass'ignor to Standard Oil Development Company, acorporation of Delaware Application 19 Claims.

My invention relates to improvements in marine foundations and in theirconstruction.

Great difliculty has always been encountered in building marinefoundations in any great depth of water, and the cost of constructingsuch foundations under present methods of construction is almostprohibitive. The driving of piles in from 500 to 1000 feet of waterisout of the question, and the sinking of caissons in such depths is wellnigh impossible, as well as economically prohibitive. Submersible bargeshave not proven successful at such depths. As a result there are no manmade mid-ocean airplane landing docks, we have been unable to core drillthe English Channel to determine the feasibility of a tunnel fromEngland to France, and we have not, as yet, been able to drill for oileconomically in more than approximately 65 feet of water.

The chief object of my invention therefore, is to provide a marinefoundation construction which will not only allow any hydraulic engineerto build such a foundation and locate it in 1000 or more feet of water,but which can be constructed in such depths of water at a costapproximating the present shallow water foundations built under presentmethods ofconstruction.

Other objects of the invention are, to provide a marine foundationconstruction which eliminates the use of piles or caissons; which willas- December 31, 1937, Serial No. 182,829

Renewed July 1, 1939 panying drawings, which are chosen for illustrativepurposes only, and in which Figure'l is a side elevation of a foundationmade in accordance with this invention, and illustrates particularly itsuse as a foundation for oil well derricks and complete drillingequipment;

Figure 2 is a side sectional view of aportion of the foundation andillustrates particularly a means of rigidly anchoring the foundation onthe marine floor;

Figure 3 is a side elevation of the lower portion of the foundation, andillustrates a preferred weight method of firmly positioning the base ofthe foundation on the marine floor in accordance with the invention;

Figures 4 and 5 are sectional side and end elevations respectively ofsimilar portions of the device illustrating construction details, aswell as details of the preferred weight anchoring method;

Figure 6 is a plan view of a portion of the base of the foundationillustrating construction details, and further details of theweightanchorsure maximum strength and stability combined with minimumweight on the ocean floor, thereby sired and placed in position on asubmerged mountain top; which may be constructed on land, towed toposition, sunk and anchored in great depths of water; which issubstantially unaffected by the tide, wind or wave action due to itsskeleton formation, its natural inertia, its use of buoyancy to maintainits vertical position, and its extremely rigid construction; and whichmay be used in the building of bridges, lighthouses, piers and mid-oceanairplane landing fields, as a foundation for geophysical instruments, aswell as for oil well drilling where the well location is in deep water.

For simplicity, the invention will be described in detail in itsadaptation to oil well drilling foundations located in 500 feet or moreof water.

The details in construction of a preferred form of my invention,together with other objects, will be better understood from thefollowing description whenread in connection with the accomstruction ofthe enlarged base;

ing method;

Figures '1 and 8 are side and plan views re- Figures 9 and 10 arefragmentary plan and side elevations respectively of similar portions ofthe foundation, illustrating details of one preferred method of bracingthe foundation;

Figures 11 and 12 are plan views of one end of a solid brace rod, Figure12 illustrating the way in which the end of the rod is treatedpreparatory to securing it to one of the other structural members, andFigure 11 illustrating the actual fasten- In general, the structure, asbuilt for oil welldrilling, consists of a derrick-like foundation 5 madeup of buoyant hollow casing uprights surrounding ahollow centralconductor pipe, all rigidly spaced apart by hollow buoyant cross braces.All cross bracing members may either be hollow and buoyant, as in Fig.15, or some may be solid according to the details of construction shownin Figs. 9 and 10, and hereinafter explained. The uprights may bevertical and parallel or they may taper inwardly from the bottom upwardto form a substantially frusto-pyramidal skeleton structure, asillustrated. In either case, the lower ends of the uprights are spacedapart sufllciently to give the entire structure a large bottom area,which area will be governed by the height to which the finishedstructure is to be built. It will be understood throughout thisdescription that the central conductor pipe 39 will be included in thestructure only when it is to be used as a well drilling foundation. Whenused for other purposes the conductor pipe is not an essential featureof the foundation, and may be eliminated. Hollow buoyant structuralmembers are used not only to facilitate the section by sectionconstruction of the foundation in the water, but to serve as a verypositive and forceful means of maintaining the foundation in a verticalposition in great depths of water. An experiment which clearlyillustrates this use of buoyancy is the holding of one end of a lightstick of wood under the surface of water and barely permitting the otherend of the stick to protrude from the water. The stick will assume andmaintain a vertical position in the water, and in comparison to theactual weight of the stick in the atmosphere, a large force must beapplied to the protruding end to move it out of vertical position.

Referring to the drawings, (Figs, 9 and 15),

the hollow upright members 20, 2|, 22, and 23 are formed preferably ofnumerous sections of thick walled hollow casing, the adjacent ends ofthe sections being rigidly fastened together by means of the usual pipejoints 24 (Fig. 1) the joints being welded to lend additional rigidity,as well as to assure a water tight joint. The end of the lowermostsections are made water tight by inserting and Welding a metal plate 25therein, as shown in Fig. 2. The horizontal compression members 26 arealso made preferably of substantially the same type hollow casing, theouter ends of which are made water tight by the welded insert platemethod, mentioned above. The ends of each of the members 26 are pre-cutto fit precisely, a template being used for the purpose. (The variousjoints are illustrated in Figs. 4, 9, and 10.) The shaped ends are thenfitted into position against the upright members, and are weldedthereto, the joint again being made water tight. As to the diagonalhorizontal brace members 21 and 21A (Figs. 9, 10 and 15), and thediagonal upright sway braces 28 and 28A (Figs. 1 to 4, 9 and 10), theymay be made either of hollow casing or of solid rods. If these bracesare hollow as designated by the numerals 2'1 and 28, the ends are madewater tight as above, and secured in position by welded template joints.If formed of solid rods, as designated by the numerals 21A and 28A theyare of considerably smaller diameter (as shown in Figs. 9 and 10), andthe ends of the rods are split longitudinally, heated and bent intoshape around the tubular members, after which they are firmly welded inposition, (See Figs. 11 and 12.) The relative advantages of the solidand the hollow diagonal brace members 21, 21A, 28, and 28A will behereinafter discussed with relation to the buoyan y desired and theparticular conditions under which the foundation is being constructed.When solid members are used it is contemplated they will preferably beformed of one continuous piece of rod between tubular members.

The details of construction thus far described are not in themselvesunusual, save for the water tight joints and the sealing of the ends ofthe various sections of easing used. The inventive idea, however, notonly includes the construction of a marine foundation, but also a methodof construction which will enable one skilled in the art to build such afoundation in 500 to 1000 feet of water. Figs. 13 and 14 particularlyillustrate the preliminary steps in the method of building thefoundation.

It is contemplated, of course, that the ultimate location of thefoundation will have first been determined, and that the exact depth ofthe water at that point also will have been determined. The latter isnecessary in order to determine the approximate size of the base neededto properly support a foundation of the required height. The conditionof the marine fioor, whether firm or soft, as well as the wave action atthe particular location must also be taken into consideration indetermining the size of the base. The condition of the marine floor willalso determine somewhat the width of the skids 29, 30,31, 32,33, and 34(Figs. 8 and 15).

When the desired size for the base has been determined, construction ofthe skids is begun. The skids are preferably formed of what is commonlyknown in the oil industry as junk casing," but the walls of theindividual sections should be water tight. I prefer to use this junkcasing to cut the cost'of construction, although any new or used casingmay be used for the purpose. All the joints are preferably screw andweld joints as previously described, and the ends of the individualmembers 35 are preferably plugged with a metal plate 25 and welded watertight, as previously described, and as illustrated in Fig. 2. As shownin Figs. 5 and 6, a number of these casing members 35 are laid side byside, and heavy boiler plate 36 is spot welded, as indicated by thenumerals 31, to the assembled casing members. The boiler plate is firstperforated at proper intervals, and the weld is made through theperforations directly to the outer wall of each casing member. (Fig. 4.)This makes a very rigid connection and holds the various casing membersrigidly side by side, yet permits these casing members to remain watertight. The boiler plate serves as the bottom of the skid. The variouscasing mem bers 35 are bent upward at their opposite ends, and theboiler plate is bent to conform. The ends of the casing members 35 arecut at different points to form a substantially arcuate prow for theskid, as shown in Figs. 5, 6, 15, and 16, and the boiler plate is outalong the ends of the casing members, as illustrated. A piece of boilerplate 52 (Figs. 4 and 6) is then similarly welded to the oppositesurface of some of the members 35 near each end of each skid. Theseplates 52 serve as bases for the uprights 20, 2|, 22, and 23, theuprights as well as the adjacent ends of the lowermost members 26 beingwelded firmly to the plates 52, thus anchoring the skids rigidly to therest of the structure. The width of the'skids may be varied to suitconditions.

After the skids have been completed, the first section of the foundationis built thereon, as previously described, and as illustrated in Fig.13. The first section will probably be about 40 feet in height, if Range3 standard length casing sections'are used for uprights. It will includethe diagonal sway braces 28 or 28A and the horizon tal compressionmembers 25. The construction of the skids and the entire first sectionmay be completed on the ocean beach, (Fig. 13) in proximity to the waterline, and when completed, the entire structure is moved into the waterThis may be done at high tide by dragging it across the beach on itsskids, tugs being the motive power; or, at low tide, double railroadtracks may be laid, one for each skid, the entire structure may beplaced on railroad car trucks and rolled to the waters edge, where itmay be easily launched at high tide, and the tracks and trucksreclaimed.

ed is offset, and it is comparatively easy to move the foundation frompoint to point in the water toward its ultimate location as each sectionis added. I prefer to build the foundation of casing members which willcontribute positive buoyancy to it during construction. For this reasonI prefer to construct the skids 29, 30, 3|, 32, 33 and 34, thecompression members 26, the sway braces 28, and the uprights 2|, 22, 23,and 24 all of 18 O. D. 96 #/ft. casing which has a net positive buoyancyof 25 per foot. Such a positive buoyancy would morethan offset theweight of solid 2" diagonal horizontal braces 21A, and of solid-2"diagonal hangers 38 (Fig. 10) for supporting the conductor pipe 39,together with the weight of an open ended conductor pipe,

- although a closed ended buoyant conductor pipe may be used if desired.The foundation, then, regardless of the stage of construction, would becomparatively easy to move by tug power. If hollow cross bracing is usedthroughout, then a standard casing may be chosen which has approximately12# buoyancy per foot.

After the first section has been completed and launched it will be towedby tug power toward its 16, the lower end of this pipe being spacedsomewhat above the skids. It is contemplated that solid hangers 38 willbe used even'though all cross bracing and sway bracing is made of hollowcasing. Any other practical means, however, may be used for supportingthe weight of this conductor pipe. When the second section has beencompleted, the structure is again pulled by tug toward its ultimatelocation until only 10 or 15 feet of it protrudes from the water. Let itbe said here that it is not contemplated that the structure can be towedto each successive new location at a speed of 5 knots or even 1 knot. Itmay require 24 hours or even '72 hours to move it from one location toanother, but even so, the man hour cost of construction will becomparatively very low. By moving it slowly, the resistance of the wateris negligible, and with the inherent buoyancy of the structureoffsetting the weight of the structural members and tending to keep thestructure upright in'the water, the moving operation is comparativelyeasy.

Section afterv section is constructed in this manner, a halter-like towline being used after the structure has grown in height. To prevent anypossibility of the buoyancy of the lower end of the structure tending totopple it over in the water, the lower end of the foundation may beweighted, by such means as is illustrated in Figs.

3 to 6, although otherweighting means may be' employed. Any means used,however, I should insure the placing of the weight atthe place lengths4| and 42 of the same size I-beam are ultimate location until the 'waterincreases in depth to about 30 feet, leaving some 10 feet of the firstsection out of the water.

water will be sufficient to offset the buoyancy of the submerged membersand to keep the first section and its skids setting firmly on the marinefloor. If a casing of comparatively high buoyancy is used, the sectionmay be weighted as required by any suitable method to keep it on the ithe construction may proceed with dispatch. With the exception of thefirst section, all sections may be constructed from a floating bargewhich carries its own hoisting machinery. together with suflicientsupplies to build several complete sections.

After the uprights and cross braces of the second section have beensecured in position, the

The weight of the casing members above the surface of the.

then placed, one on each side of the central beam 7 40, as shown, andwelded into position, their tops forming a weight supporting platform. Atotal of four or more of these platforms are built, as shown in Fig. 15.As shown in Figs. 4 and 5, the lowermost compression members 26 passthrough suitably sized andproperly located holes in the I-beams 40, 4|and 42, and may be welded to the adjacent portion thereof, if desired.To the platform formed by the tops of these I-beams, is welded the lowerend of a string of casing 43, and this string of casing is built up,section by section, as the rest of the structure increases in height.Surrounding the string 43 is a second string of casing 44 which is alsobuilt up section by section, with the rest of the foundation.

The string 44 is preferably formed of flush joint casing sections, and aheavy outstanding flange 45 is firmly welded about its lower end. Theupper ends of these two strings of casing 43 and 44 are held in positionby means of slips 46 and split spiders 41 (Fig. 4), temporarilysupported on timber false work 48, all of which may be moved upward fromcross brace to cross brace, as the foundation increases in height,section by section. The bottom surface of the flange 45 rests freely onthe I-beam platform, while its upper surface is adapted to receiveweights, such as railroad car'wheels 49. It will be remembered first twosections of the conductor pipe 39 are secured in position, as shown inFigs. 14, 15, and

that the lower end of the inner string 43 only is welded to the I-beams,and that the outer string 44 is entirely free to move longitudinallywith respect to the inner string. The joints of the outer string, beingflush, present no obstruction to the downward progress of railroad carwheels or other similar weights dropped over the upper end of thestring. I prefer to use junk railroad car wheels for weights because oftheir compact form. They weigh from 750# to 900#, only vary in diameterfrom 33" to 36", and can be obtained with 8", 9", or 10 hub diameters.With such a method of weighting, the weights may be added as needed, andmay also be recovered simply by pulling up the outer string of casing 44and reclaiming the various casing sections as they emerge. The flange45, being of larger diameter than .the holes in the weights, preventsthe weights from slipping off the lower end of the string 44, and thestring 43 acts as a guide to prevent injury to the cross bracing or swaybracing as the weights are lifted through the interior of the structure.Necessarily, the first section of these two strings of casing 43 and 44,must be placed in position and their upper ends temporarily supported asdescribed, before the first section of the foundation is launched. Withthis method of weighting it will be easily seen that more buoyant casingsections than previously mentioned can be used for all structuralmembers, and that the buoyancy can thus be utilized to keep the entirestructure vertical in the water under any and all conditions on or nearthe surface of the water, regardless of the stage of con struction.

After the foundation has been towed to its ultimate location, and thelast section has been erected (the upper end of which should in mostcases be from 40 to 50 feet above sea level), an alternative method ofanchoring may be-used if desired, in place of the weights. Fig. 2illustrates this alternative method, which will ordinarily be used onlywhen the foundation is to be permanently located. To properly anchor thefoundation according to this method, a suitable platform is constructed(bridge truss construction approximately 10 feet deep) and a rotarydrilling rig is positioned on the platform. The

rig is positioned over each of the uprights 20, 2|,

22 and 23 in turn, and the drill stem lowered through these uprights.The respective plates in the lower end of each upright are drilledthrough and penetration into the ocean floor is continued to a desireddepth, say 500 feet. Casing Si is then set in each hole through theupright members of the foundation, or if preferred the drill pipe may beleft in the hole for this purpose. Cement is then introduced, and theinner casing ii is cemented in the manner common to oil well drillingpractice, the cement rising about the outside of the casing, as well asinto the upright leg members. (See Fig. 2.) With a casing 5| thuscemented in each of the upright members of the foundation a very firmanchorage is provided and, if desired, the strings of casing 43 and 44together with the weights 49 ,may then be removed, as previouslydescribed. To prevent any possibility of relative longitudinal movementbetween the leg members and their respective inner casings 5|, a casinghead 53 may be attached to the upper end of each leg member and to theupper end of its respective inner casing 5|.

Still another alternative method of maintaining the foundation inupright position against wind and wave action is illustrated in Figs. 7and 8. In these figures is illustrated an enlarged octagon shaped base,there being two longer skids I0 and 3| substituted for the shorter skids33 and 34, and two skids I! and 32 added at the side edges. The skidsare formed in substantially the same manner, and the central uprightportion is made substantially the same as the base of the foundationillustrated in Figs. 1, 3 and 13 to 16 inclusive. For purposes ofclarity, only the main structural members have been shown in these twofigures, the cross bracing and sway bracing being omitted. It iscontemplated, however, that suitable bracing will be used, that thecasing sections used will be water tight, and thatthe various jointswill be fitted and welded, as previously described. This type of basegives approximately six times the base area and fully three times thestability, completely ignoring the buoyancy factor in bothconstructions.

It is believed that the inventive idea has been fully disclosed by theabove description, and that said description would enable those familiarwith the art to practice the invention. Figures 9 to 12 simplyillustrate the use of solid sway braces 25A, and solid diagonalhorizontal members "A, as opposed to the use of hollow brace members 21and 28 as shown in the other figures.

I point out that a foundation constructed in accordance with myinvention will have a high degree of stability. The features whichcontribute stability are: the large base firmly anchored in a horizontalplane (by either or both of the two methods disclosed) with the rigidupright skeleton structure rigidly secured thereto; the inherentbuoyancy of the structure, which tends to keep it in vertical position;the natural inertia of the structure due to its own weight in theatmosphere; and the resistance of the water surrounding the submergedstructural members against movement of the members in any direction. Tomove the foundation away from vertical position, then, the force wouldhave to be suflicient to overcome all these factors combined.

Any wind, water, or wave action would necessarily be applied to thatportion of the foundation which protrudes from the surface of the water,or to that portion immediately adjacent the water level. Due to itsskeleton construction, the protruding portion presents comparativelylittle resistance to such forces. Considering this small surfaceresistance together with the. four above mentioned stability features,it

' will be easily understood that the completed structure will have ashigh a degree of stability in deep water as the larger, more bulkyfoundations now in use have in shallow water.

While I have described and illustrated specific embodiments of myinvention I am aware that numerous alterations and changes may be madetherein and I do not wish to be limited except by the prior art and bythe scope of the appended claims.

I claim:

1. An elongated marine foundation comprising a plurality of rigidindividually water buoyant structural sections of skeleton formationsuperimposed one upon the other and rigidly secured together; and aplurality of substantially flat bottomed skids rigidly secured to thelowermost section and adapted to facilitate the moving of the skeletonstructure across the ocean floor at any stage of its construction, andalso adapted to serve as a base for the structure.

2. An elongated marine foundation comprising a plurality of rigid waterbuoyant structural sections of skeleton formation superimposed one uponthe other and rigidly secured together; a plurality of substantiallyfiat bottomed skids rigidly secured to the lowermost section' andadapted to facilitate the moving of the skeleton structure from place toplace on the ocean floor at any stage of construction as well as toserve as a base for the structure; and means extending from the top ofthe uppermost section to said skids for guiding weights to apredetermined resting place on said skids.

3. A marine foundation comprising: a plurality of spaced sealed airfilled hollow water buoyant upright leg members; intersecting spacedsealed air filled hollow water buoyant cross brace members rigidlysecured at intervals to said leg members; diagonally disposed horizontaland upright sealed hollow water buoyant bracing tension members likewiserigidly secured to said leg members and to each other where theyintersect, all of said members together forming a rigid buoyantelongated skeleton structure; spaced weights positioned on the base ofsaid structure; and means for guiding said weights from the top of saidstructure to predetermined locations on its base, whereby all thebuoyancy of the elongated structure which is above said weights and issubmerged plurality otjspaced sealed air filled hollow water buoyantcross brace members rigidly secured at intervals to said leg members;diagonally disposed horizontal members and diagonally disposed uprightmembers rigidly secured to said leg Y members, to said cross bracemembers, andto brace members, their opposite ends rigidly sein a liquidis utilized to maintain said structure in vertical position in theliquid.

4. A marine foundation comprising a multiplicity of' water buoyantstructural members including spaced upright leg members, compressionbrace members, and tension brace members all rigidly secured together ina manner to form a water buoyant rigid skeleton structure; weights forthe base of said structure suflicient to permit its inherent buoyancy tomaintain the structure in an upright position in water while permittingits upper end to protrude from the surface of the water; and means forguiding additional weights from the protruding end of said structure toits base for causing its base to seat solidly on the marine floor.

5. Organization as described in claim 4, and means extending from theinside of each of said leg members, out through the lower ends thereofand into the ocean fioor for firmly anchoring said foundation inpermanent position.

6. A derrick-like marine foundation comprising a multiplicity of hollowsealed water buoyant structural members including spaced upright legmembers, horizontal cross brace members having their opposite endsrigidly secured at intervals to said leg members, diagonal horizontalcross brace membershaving their opposite ends rigidly secured atintervals to opposed ones of said leg members and to each other wherethey intersect,

and diagonal upright compression brace members having their oppositeends rigidly secured to opposite ends of certain proximate onesbf saidfirst mentioned horizontal cross brace members as well as to adjacentones of said leg members, said aforementioned members together forming awater buoyant rigid skeleton structure; removable weights for the baseof said structure sufficient to permit its inherent buoyancy to maintainthe structure in upright position in water while permitting its upperend to protrude from the surface of the water; and means extending fromits protruding upper endto the base of said structure for guiding saidweights through the water to a particular point on said base, and forremoving said weights as desired.

7. A marine foundation for oil well drilling comprising: a plurality ofspaced sealed air filled water buoyant upright leg members; a greatercured to adjacent ones of said leg members at intervals; a plurality ofdiagonal horizontal cross brace members intersecting in pairs and eachpair having their opposite ends rigidly secured to opposed ones of saidleg members; diagonal upright sway brace members connected rigidly toadjacent ones of said leg members at intervals and disposed betweenopposite ends of certain ones of said first mentioned horizontal crossbrace members and rigidly secured thereto; a plurality of substantiallyfiat bottomed skids each rigidly secured to the lowermost ends of aplurality of said leg members as well as to certain of the lowermostcross brace members and adapted to facilitate the moving of the entirefoundation from point to point on the ocean fioor as well as to serve asa base for the foundation; and weight guiding means extending from thetop of the structure to said skids for guiding weights to apredetermined resting place on said skids.

10. A marine foundation comprising: a plurality of spaced sealed airfilledhollow upright leg members; and a greater plurality of spacedsealed air filled hollow cross brace members rigidly secured to adjacentones of said leg members to form a completely rigid skeleton structure,said structure, as a unit, being substantially symmetrical and having aslightly negative buoyancy when submerged. in water.

11. -A marine foundation comprising: a plu-' rality of spaced sealed airfilled hollow upright leg members; a plurality of structural cross bracemembers secured to adjacent ones of said leg members to form acompletely rigid skeleton structure, the buoyancy of said leg membersbeing sufiicient to substantially offset the weight of the entirestructure making it only very slightly heavier than the water which itdisplaces when it is submerged in a body of water; and means forweighting the lowermost end of said structure at predetermined pointsafter it is submerged in water.

12. The method of constructing a marine foundation which comprisesbuilding a buoyant first section on dry land; launching and towing saidfirst section toward its ultimate location to a point at which the wateris slightly less in depth than the height of said first section;building a buoyant second section on the upper protruding end of saidfirst section; towing the partially completed buoyant structure farthertoward its ultimate location to a point at which the water is slightlyless in depth than the height of the two combined sections; weightingthe base of the buoyant structure as needed to maintain it in an uprightposition in the water; repeating these steps until the foundation hasreached its required height and until it has reached its ultimatelocation; and anchoring the base of the foundation firmly on the marinefloor.

13. An elongated marine foundation comprising a plurality of rigid waterbuoyant, structural sections of skeleton formation, superimposed oneupon the other and rigidly secured together, and

a substantially flat bottomed skid-like base secured to the lowermostsection and adapted to facilitate the moving of the skeleton structurefrom place to place on the bed of, a body of water at any stage ofconstruction, aswell as to serve as a base for the structure.

14. An elongated marine foundation comprising a-plurality of rigid waterbuoyant, structural sections of skeleton formation, superimposed oneupon the other and rigidly secured together, a substantially flatbottomed base member rigidly secured to the lowermost section andadapted to facilitate the moging of the skeleton structure from place toplace on the bed of a body of water at any stage of construction as wellas to serve as s,ase',ess

ber when the latter is in the desired anchoring position and to becemented in place in the earth.

17. A method for anchoring a marine foundation for oil well drillingcomprising providing on said foundation a plurality of hollow legmembers rigidly secured to said foundation, passing a drill stem-througheach of said members and drilling into the earth below the foundation asubstantial distance, inserting a tubing through each of said hollow legmembers and into the boreholes so drilled and forcing cementing materialinto said boreholes and up around said tubing.

18. A method for anchoring a marine foundation for oil well drillinghaving a derrick structure provided with hollow leg members terminatingadjacent the bottom of said foundation comprising inserting a drillstemin each of a plurality of said leg members and drilling into the earthboreholes in alignment with corresponding leg members, placing tubing ineach of said leg members extending into its corresponding borehole andforcing cementing material into said boreholes and up around saidtubing.

19. A marine foundation foroil well drilling comprising a plurality ofspaced sealed gas filled, water-buoyant, upright leg members, a greaterplurality of spaced, sealed, gas-filled, waterbu'oyant, cross-barmembers rigidly secured to said leg members, all of said memberstogether forming a rigid. buoyant, elongated structure, a conductor pipecentrally placed within said structure. and means for rigidly holdingsaid conductor pipe in spaced relation to said leg members. HENRY EMMETIGROSS.

